XMM-Newton
Science Analysis System: User Guide

6.6 Running the OM data processing

The data package received by the investigator contains OM data which normally
do not necessitate further processing for the purpose of calibration.
However, a user may want to apply the most recent calibration, or to change
some default parameters to e.g. improve the source detection on his/her data.
It may not be necessary to run the complete chains, but just some tasks.
All this can be done interactively.

The SAS_ODF environment variable shall be set to the directory containing
the raw data, or directly to the SAS summary file, and access to calibration files
shall be set through cifbuild (see § 2.3).

The OM tasks and chains can be run on a working directory different from where
the raw (ODF) data reside, providing that the environment variables are properly
set.

Invoking omichain, omfchain or omgchain will automatically
start the processing of all referred OM data. The duration of the process
will depend on the number of exposures and windows, and at the end, the
working directory will contain the processed files described before.
Some intermediate files will be preserved as well.

Currently only omichain can accept parameters to limit the processing
to a given filter or a given exposure:

Some of the default parameters used by individual
tasks can also be tuned. To see all possible parameters, run:

omichain -h

In the following examples, it is shown how to run all the tasks that form a chain.
The fundamental parameters needed by each task are outlined. For a detailed
description of all possible parameters, the user is referred to the
section of the SAS online documentation with a description of all the SAS tasks at:

For a better understanding of the processing done by any of the chains,
it is recommended to re-direct their screen output to a log file. This will
allow the user to examine the process and to see if there is any error or
anomaly.

If a user wants to fully understand the process, then running a chain task by
task may be useful. In this case it is recommended to have the raw data to
be processed and the auxiliary files in the working directory.